The invention relates to a wireless communication system (100), comprising a plurality of radio nodes, each being able to operate at least as a router node (104) or as a non-router node (104). Each of the plurality of radio nodes is configured to: detect density of the router nodes (104) within its neighbourhood, and make a decision based on the detected density whether to operate as a router node (104) or as a non-router node (106). The invention relates also to a role selection method and a radio node device (104, 106, 500) for the wireless communication system (100).
Legal claims defining the scope of protection, as filed with the USPTO.
1. A wireless communication system ( 100 ), comprising: a plurality of radio nodes, each of the plurality of radio nodes being able to operate at least as a router node ( 104 ) or as a non-router node ( 104 ), wherein each of the plurality of radio nodes is configured to: detect density of the router nodes ( 104 ) within its neighbourhood, and make a decision based on the detected density whether to operate as a router node ( 104 ) or as a non-router node ( 106 ), wherein the decision is provided by comparing the detected density to a scalable density margin, and wherein the density margin is scaled with one or more hysteresis values to mitigate unnecessary role changes.
2. The system ( 100 ) according to claim 1 , wherein the decision is dependent on the current operating role of said node.
3. The system ( 100 ) according to claim 2 , wherein the density of the router nodes ( 104 ) is defined as a ratio between number of occupied superframe, SF, slots per access cycle ( 206 ) and number of all SF slots per access cycle ( 206 ) in a Frequency-Time Division Multiple Access, FTDMA, table.
4. The system ( 100 ) according to claim 2 , wherein the decision to change the role from router node to non-router node is prevented, based on the node having a route to a sink node ( 102 ), and there are one or more neighbour nodes in router role that do not have a route to a sink node ( 102 ).
5. The system ( 100 ) according to claim 1 , wherein the density margin has a common value throughout the system.
6. The system ( 100 ) according to claim 1 , wherein the density margin is scaled with a node specific route cost, decreasing or increasing a probability of said node to choose the router role.
7. The system ( 100 ) according to claim 6 , wherein a probability of said node to choose the router role decreases, when the route cost increases.
8. The system ( 100 ) according to claim 5 , wherein the density margin is scaled with a node specific route cost, decreasing or increasing a probability of said node to choose the router role.
9. The system ( 100 ) according to claim 1 , wherein the density margin is scaled according to radio interference within the neighbourhood of the node, decreasing or increasing a probability of the node to choose the router role and decreasing or increasing the router density within the neighbourhood of the node.
10. The system ( 100 ) according to claim 1 , wherein the decision to change the role has been valid at least predefined time before performing the role change.
11. The system ( 100 ) according to claim 1 , wherein the density of the router nodes ( 104 ) is defined as a ratio between number of occupied superframe, SF, slots per access cycle ( 206 ) and number of all SF slots per access cycle ( 206 ) in a Frequency-Time Division Multiple Access, FTDMA, table.
12. The system ( 100 ) according to claim 1 , wherein the decision to change the role from router node to non-router node is prevented, if the node has a route to a sink node ( 102 ), and there are one or more neighbour nodes in router role that do not have a route to a sink node ( 102 ).
13. A radio node device ( 104 , 106 , 500 ) for wireless communication system ( 100 ), being able to operate at least as a router node ( 104 ) or as a non-router node ( 106 ) and comprising: a microcontroller ( 504 ), and a radio transceiver ( 506 ), wherein, the radio node device ( 102 , 104 , 106 , 500 ) is configured to: detect, by the microcontroller ( 504 ), density of the router nodes ( 104 ) within its neighbourhood, and make a decision, by the microcontroller ( 504 ), based on the detected density whether to operate as a router node ( 104 ) or as a non-router node ( 106 ), wherein the decision is provided by comparing the detected density to a scalable density margin, and wherein the density margin is scaled with one or more hysteresis values to mitigate unnecessary role changes.
14. A role selection method for the radio node device ( 104 , 106 , 500 ) of claim 13 in a wireless communication system ( 100 ), wherein the method comprises: detecting ( 302 ), by the microcontroller ( 504 ), density of the router nodes ( 104 ) within its neighbourhood, and making a decision ( 304 ), by the microcontroller ( 504 ), based on the detected density whether to operate as a router node ( 104 ) or as a non-router node ( 106 ), wherein the decision is provided by comparing the detected density to a scalable density margin, and wherein the density margin is scaled with one or more hysteresis values to mitigate unnecessary role changes.
15. A non-transitory computer readable medium having stored thereon a computer program that when executed by a computer processor causes the method of claim 14 to be performed.
16. A non-transitory computer readable medium comprising a computer program that when executed by the microcontroller causes the method of claim 14 to be performed.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
May 25, 2018
December 3, 2019
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